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71.
Bouchet A Brotin T Linares M Ågren H Cavagnat D Buffeteau T 《The Journal of organic chemistry》2011,76(10):4178-4181
ECD and NMR experiments show that the complexation of propylene oxide (PrO) within the cavity of an enantiopure water-soluble cryptophane 1 in NaOH solution is enantioselective and that the (R)-PrO@PP-1 diastereomer is more stable than the (S)-PrO@PP-1 diastereomer with a free energy difference of 1.7 kJ/mol. This result has been confirmed by molecular dynamics (MD) and ab initio calculations. The enantioselectivity is preserved in LiOH and KOH solutions even though the binding constants decrease, whereas PrO is not complexed in CsOH solution. 相似文献
72.
Dr. Thomas Varlet Damien Bouchet Elsa Van Elslande Dr. Géraldine Masson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(56):e202201707
We report herein a convenient and scalable dearomative hydroacylation reaction of indoles. Employing readily available aldehydes as the acyl source and TBADT as an inexpensive direct HAT photocatalyst, a variety of indoles derivatives were converted into synthetically interesting 2-acylindolines in good to excellent yields as well as great diastereoselectivity under mild conditions. An asymmetric version of the reaction was successfully developed and an experimental mechanistic investigation was carried out in order to gain further insights on the assumed reaction pathway. 相似文献
73.
The different forms of second order elasticity operators, in Mindlin’s strain-gradient elasticity, are given for a bi-dimensional physical space. These different forms are obtained according to the different symmetry classes of a material media. Dimensional aspects are discussed together with observations made on the physical behavior of such a media. 相似文献
74.
Determination of cis and trans configurations in pentahydrobenzopyranopyrroles by FT-IR spectroscopy
Benoît Bertrand Christian Nisole Jean-Michel Drancourt Thierry Dubuffet Jean-Paul Bouchet Jean-Paul Volland 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》1996,52(14):1921-1923
A method of distinguishing cis and trans isomers in polyheterocycles containing β,β′-disubstituted pyrrolidines is described. It is based on the relative absorbance of the Bohlmann bands and the normal symmetric CH stretching bands. The method is applied using FT-IR spectroscopy in solution and coupled with gas chromatography. An interpretation is given, with the help of molecular computing. 相似文献
75.
76.
Rodrigo S Chaves Thaiany Q Melo Stephanie A Martins Merari FR Ferrari 《BMC neuroscience》2010,11(1):144
Background
Protein aggregates containing alpha-synuclein, beta-amyloid and hyperphosphorylated tau are commonly found during neurodegenerative processes which is often accompanied by the impairment of mitochondrial complex I respiratory chain and dysfunction of cellular systems of protein degradation. In view of this, we aimed to develop an in vitro model to study protein aggregation associated to neurodegenerative diseases using cultured cells from hippocampus, locus coeruleus and substantia nigra of newborn Lewis rats exposed to 0.5, 1, 10 and 25 nM of rotenone, which is an agricultural pesticide, for 48 hours. 相似文献77.
Aggarwal MM Ahammed Z Alakhverdyants AV Alekseev I Alford J Anderson BD Anson D Arkhipkin D Averichev GS Balewski J Barnby LS Baumgart S Beavis DR Bellwied R Betancourt MJ Betts RR Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Biritz B Bland LC Bonner BE Bouchet J Braidot E Brandin AV Bridgeman A Bruna E Bueltmann S Bunzarov I Burton TP Cai XZ Caines H Calderón de la Barca Sánchez M Catu O Cebra D Cendejas R Cervantes MC Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH Chen JY 《Physical review letters》2010,105(20):202301
The contribution of B meson decays to nonphotonic electrons, which are mainly produced by the semileptonic decays of heavy-flavor mesons, in p + p collisions at √s=200 GeV has been measured using azimuthal correlations between nonphotonic electrons and hadrons. The extracted B decay contribution is approximately 50% at a transverse momentum of pT≥5 GeV/c. These measurements constrain the nuclear modification factor for electrons from B and D meson decays. The result indicates that B meson production in heavy ion collisions is also suppressed at high pT. 相似文献
78.
Buffeteau T Cavagnat D Bouchet A Brotin T 《The journal of physical chemistry. A》2007,111(6):1045-1051
Vibrational absorption and circular dichroism (VCD) spectra of (-)-(1S,3R)-camphanic acid have been measured in deuterated chloroform solutions at different concentrations (0.005, 0.045, and 0.200 M) in the mid-infrared spectral range. Experimental spectra have been compared with the density functional theory (DFT) absorption and VCD spectra, calculated using the B3PW91 functional and cc-pVTZ basis set for three conformers of both the monomer and the dimer forms of (-)-(1S,3R)-camphanic acid. These calculations indicate that, in the dilute solution, the conformer with intramolecular hydrogen-bonding between the hydroxyl and lactone groups is of lowest energy and represents 70% of the different monomer conformers at room temperature, whereas, in concentrated solution, the dimer formed by intermolecular hydrogen-bonding of carboxyl groups of the two distinct monomer conformations is stabilized. The vibrational absorption and circular dichroism spectra calculated from the Boltzmann population of the individual monomer and dimer conformers are in very good overall agreement with the corresponding experimental spectra, allowing the absolute conformation and configuration of (-)-(1S,3R)-camphanic acid in dilute and concentrated solution, respectively. Experiments were also performed on (-)-(1S,3R)-camphanic chloride for which the populations predicted by DFT calculations are found to be in disagreement with those deduced from experimental spectra. 相似文献
79.
Bouchet A Brotin T Linares M Ågren H Cavagnat D Buffeteau T 《The Journal of organic chemistry》2011,76(5):1372-1383
A new water-soluble cryptophane 1 derivative (penta-hydroxyl cryptophane-A) has been synthesized from cryptophanol-A and the chiroptical properties of its two enantiomers MM-1 and PP-1 have been studied by polarimetry, electronic circular dichroism (ECD), and vibrational circular dichroism (VCD). Cryptophane 1 shows specific circular dichroism responses upon complexation that depend on the size of the guest and on the nature of the counterion (Li(+), Na(+), K(+), Cs(+)) present in the solution. In LiOH and NaOH solutions, chiroptical changes induced by the encapsulation of guests and by the presence of cations in the vicinity of hosts can be interpreted from molecular dynamics (MD) and ab initio calculations by subtle conformational changes of the bridges. In KOH solution, the exchange dynamics is dependent on the size of the guest molecules, whereas in CsOH solution no encapsulation effect is observed whatever the size of the guest molecule. This last behavior comes from the fact that host 1 exhibits a very high affinity for cesium cations. 相似文献
80.
J. Barré F. Bouchet T. Dauxois S. Ruffo 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):577-591
We study an analytically tractable model with long-range interactions for which an out-of-equilibrium very long-lived coherent structure spontaneously appears. The dynamics of this model is indeed
very peculiar: a bicluster forms at low energy and is stable for very long time, contrary to statistical mechanics predictions. We first explain the
onset of the structure, by approximating the short time dynamics with a forced Burgers equation. The emergence of the bicluster
is the signature of the shock waves present in the associated hydrodynamical equations. The striking quantitative agreement
with the dynamics of the particles fully confirms this procedure. We then show that a very fast timescale can be singled out
from a slower motion. This enables us to use an adiabatic approximation to derive an effective Hamiltonian that describes
very well the long time dynamics. We then get an explanation of the very long time stability of the bicluster: this out-of-equilibrium
state corresponds to a statistical equilibrium of an effective mean-field dynamics.
Received 28 February 2002 / Received in final form 24 July 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: Thierry.Dauxois@ens-lyon.fr
RID="b"
ID="b"UMR-CNRS 5672
RID="c"
ID="c"UMR 5582 相似文献